mongodb-generic-repository/MongoDbGenericRepository/DataAccess/Read/MongoDbReader.Project.cs

using System;
using System.Collections.Generic;
using System.Linq.Expressions;
using System.Threading;
using System.Threading.Tasks;
using MongoDB.Driver;
using MongoDbGenericRepository.Models;

namespace MongoDbGenericRepository.DataAccess.Read
{
    public partial class MongoDbReader
    {
        /// <inheritdoc />
        public virtual async Task<TProjection> ProjectOneAsync<TDocument, TProjection, TKey>(
            Expression<Func<TDocument, bool>> filter,
            Expression<Func<TDocument, TProjection>> projection,
            string partitionKey = null,
            CancellationToken cancellationToken = default)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
            where TProjection : class
        {
            return await HandlePartitioned<TDocument, TKey>(partitionKey)
                .Find(filter)
                .Project(projection)
                .FirstOrDefaultAsync(cancellationToken);
        }

        /// <inheritdoc />
        public virtual async Task<List<TProjection>> ProjectManyAsync<TDocument, TProjection, TKey>(
            Expression<Func<TDocument, bool>> filter,
            Expression<Func<TDocument, TProjection>> projection,
            string partitionKey = null,
            CancellationToken cancellationToken = default)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
            where TProjection : class
        {
            return await HandlePartitioned<TDocument, TKey>(partitionKey).Find(filter)
                .Project(projection)
                .ToListAsync(cancellationToken);
        }

        /// <inheritdoc />
        public virtual TProjection ProjectOne<TDocument, TProjection, TKey>(
            Expression<Func<TDocument, bool>> filter,
            Expression<Func<TDocument, TProjection>> projection,
            string partitionKey = null,
            CancellationToken cancellationToken = default)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
            where TProjection : class
        {
            return HandlePartitioned<TDocument, TKey>(partitionKey).Find(filter)
                .Project(projection)
                .FirstOrDefault(cancellationToken);
        }

        /// <inheritdoc />
        public virtual List<TProjection> ProjectMany<TDocument, TProjection, TKey>(
            Expression<Func<TDocument, bool>> filter,
            Expression<Func<TDocument, TProjection>> projection,
            string partitionKey = null,
            CancellationToken cancellationToken = default)
            where TDocument : IDocument<TKey>
            where TKey : IEquatable<TKey>
            where TProjection : class
        {
            return HandlePartitioned<TDocument, TKey>(partitionKey).Find(filter)
                .Project(projection)
                .ToList(cancellationToken);
        }
    }
}